Can I edit an armature's size through its bounding box?
An armature object doesn't provide it's bounding box size. However the mesh object of your character does. You can scale your mesh object until the height is to your liking (the dimensions are visible in the properties sidebar). By selecting your armature, then shift selecting your mesh, the mesh object is active and will display it's dimensions as both objects get scaled together.



If your character is made of several items you will only see the size of the active object, a trick there is to add a cube and size it to the height you want, then use it as a reference and resize your character to fit.